.box_2 {
  width: 100px;
  height: 100px;
  border-radius: 20px;
  background-image: url(../oneemoji.jpg);
  animation: pos 5s infinite;
  background-position: top left;
  background-size: 300px;
}

@keyframes pos {
  50% {
    background-position: center;
  }
}